Opioid dependence (OD) is a common, chronic, relapsing addiction with a substantial genetic component. Central to the neurobiology of OD is the mu opioid receptor (MOR), through which most of the rewarding effects of opioids are mediated. The goal of this developing center is to enhance our understanding of MOR in OD through mechanistic MOR research, mouse model studies and human OD genetic investigations. The Administrative Core (AC) will provide financial, logistical and organizational support to the developing center. The AC will serve three functions: (1) provide scientific leadership and evaluate center activities, (2), offer administrative support and (3) organize training and communication activities. The AC will include the Pis of the projects (Drs. Ferraro, Blendy, Levenson and Berrettini), as an executive committee. It will also include an Internal Advisory Board of three outstanding professors with expertise in areas vital to the developing center. These professors are Charles O'Brien, MD, PhD, Ted Abel, PhD and Ellen Unterwald, PhD. An External Advisory Board will also be constituted, after notification of funding, in accordance with the RFA. The executive committee, with the Internal and External Advisory Boards, will direct the scientific projects and cores, and will evaluate center progress. The AC will co-ordinate these efforts. In addition, the AC will provide support for the training initiatives of the developing center, including the introduction of an interdisciplinary course on opioids, accessible to graduate students and post-doctoral fellows at the University of Pennsylvania. Finally, the AC with organize, facilitate and provide logistic support for a course on OD, to be offered to graduate students, post-doctoral fellows and undergraduate students.